I think the method has been summed up pretty well from the previous posts, i.e. alot of fuel + no passengers = great range. Also, of course, they don't/can't fly non-stop. They go north in both cases (through Canada/Greenland/Iceland for the Atlantic, Alaska/Russia/Japan for the Pacific). Also, I don't know about the Airbus', but the 737NG family actually has the range to make an Eastern US to Western Europe crossing, with passengers.
Now, here's another one for you: Imagine Bombadier's delivery flight from their CRJ plant to customers in Asia. That would be a long trek in a regional jet, even without passengers!
Honor the warriors, not the war.